反硝化除磷脱氮系统中DPB的驯化富集培养

反硝化同时脱氮除磷系统中反硝化除磷菌(DPB)的培养驯化状况,将直接影响污水中氮磷等营养元素的同时去除效率以及系统的高效稳定运行,为此本实验研究设计了一套以实际生活污水为处理对象的双污泥反硝化脱氮除磷工艺流程,采用逐渐过渡的培养方式,为DPB创造良好的厌氧/缺氧交替环境,即创造特定的适合DPB生存的环境条件让其进行自然选择,以筛选出来需要的DPB菌.结果表明,通过15d的间歇曝气的厌氧/好氧(A/O)运行方式可以对PAOs进行快速诱导;第二阶段,通过好氧曝气时间的逐渐减少,缺氧段投加硝酸氮的厌氧/好氧/缺氧(A/O/A)运行模式,25d左右可达到强化诱导反应器里面的DPB占PAOs的比例;最后让DPB在严格的厌氧/缺氧交替环境下进行富集培养19d,通过这种逐渐过渡培养的方式获得了对所需要的DPB菌的成功诱导富集,该菌的成功驯化培养为市政生活污水中的氮磷同时高效稳定去除提供了一种新方法.     

活性污泥储存与消耗乙酸基质的试验研究与模拟

同时贮存与生长理论认为,活性污泥吸收有机碳基质同时用于储存和生长.向SBR反应器投加不同浓度乙酸基质,监测活性污泥氧利用速率(OUR)、聚羟基烷酸盐(PHA)和出水COD的变化,运用活性污泥同时贮存与生长理论分析有机碳储存与消耗过程的特征.结果表明,饱食期结束与COD消耗至最低水平、PHA浓度出现最大值和OUR由最大值急速下降相对应;在饱食阶段,基质贮存OUR是利用外部基质直接生长OUR的2倍.随基质投加历时延长,饱食期平均OUR和最大OUR均下降,PHA产率降低,甚至出现PHA净消耗.因此,基质投加方式对有机碳基质储存与消耗有重要影响.     

喷射床电沉积法处理含铜废水的试验研究

以实验室模拟含铜废水为研究对象,采用恒电流喷射床微粒电沉积法对其进行条件试验.结果表明,在pH=3.0、沉积液质量浓度为1 g/L、恒电流为10 A、阴极微粒粒径为1.8 mm、沉积液温度为20℃、鼓入氮气的条件下,铜离子的最大去除率为87.64％,平均电流效率可以达到81.53％,较同等条件下平板电极提高了63％.喷射床微粒电极采用的阴极微粒电极具有较大的比表面积,微粒的喷射循环能够有效地消除沉积过程中出现的浓差极化现象,鼓入氮气可以明显降低沉积液中的溶解氧浓度,从而抑制沉积的金属铜返溶,因此,喷射床微粒电沉积法在处理含铜废水时能够获得较高的电沉积率和电流效率.     

Can Rapid Assessment Protocols Be Used to Judge Sediment Impairment in Gravel‐Bed Streams? A Commentary

Land management agencies commonly use rapid assessments to evaluate the impairment of gravel‐bed streams by sediment inputs from anthropogenic sources. We question whether rapid assessment can be used to reliably judge sediment impairment at a site or in a region. Beyond the challenges of repeatable and accurate sampling, we argue that a single metric or protocol is unlikely to reveal causative relations because channel condition can result from multiple pathways, processes, and background controls. To address these concerns, a contextual analysis is needed to link affected resources, causal factors, and site history to reliably identify human influences. Contextual analysis is equivalent in principle to cumulative effects and watershed analyses and has a rich history, but has gradually been replaced by rapid assessment methods. Although the approaches differ, rapid assessment and contextual analysis are complementary and can be implemented in a two‐tiered approach in which rapid assessment provides a coarse (first‐tier) analysis to identify sites that deserve deeper contextual assessment (second‐tier). Contextual analysis is particularly appropriate for site‐specific studies that should be tailored to local conditions. A balance between rapid assessment and contextual analysis is needed to provide the most effective information for management decisions.     

Prediction of Total Sediment Load in Sand‐Bed Rivers in Korea Using Lateral Distribution Method

A new method for numerically predicting the total sediment load in a river is proposed. The method can be used to predict the total sediment load with information on channel geometry and slope, flow, and bed materials. The conventional method uses a 1D approach that assumes the channel has a wide rectangular shape. However, the proposed method computes depth‐averaged velocity over the width and predicts the total sediment load based on the flow computations. The new method, therefore, is expected to predict better if the flow changes significantly in the lateral direction. The proposed method was applied to three large sand‐bed rivers in Korea, where information is available regarding suspended sediment. Five formulas were tested of use in making total sediment load computations, namely Engelund‐Hansen's, Ackers‐White's, Yang's, Brownlie's, and Karim's formulas. The predicted total sediment loads are compared not only with measured data but also with results calculated using the 1D approach. Discrepancy ratios between the predicted and measured total sediment loads are given and the results are discussed.     

生活垃圾生物预处理后筛分及分选特性试验研究

堆肥化技术作为垃圾预处理方式在国内外已得到了广泛认可.本文通过现场试验,研究了生物预处理对垃圾筛分和分选特性的影响.结果表明,预处理后垃圾含水率降低了7.69%,堆体的体积从275 m~3减少到183 m~3,垃圾的容重从最初的356 kg·m~(-3)增加到470 kg·m~(-3).经过生物预处理,有机物不断被降解.预处理可以提高筛分后筛下物比例,预处理后的筛下物百分比提高了17%.预处理对可回收成分(金属、塑料、纸张、玻璃和布匹等)分选效率都较新鲜垃圾有不同程度的提高,对金属分选效果提高最显著,达到22.01%.本研究表明,生物预处理对垃圾筛分和分选均具有积极的作用,可以提高后期资源回收利用率.     

北京大气PM2.5与惰性SiO2的生物毒性比较

以惰性SiO2颗粒作为模式颗粒,与野外采集PM2.5分别作用于模式生物粟酒裂殖酵母菌(Schizosaccharomyces pombe),旨在通过对比实验确定PM2.5致毒的主要因素.采用紫外分光光度法测定细胞增值率,环境扫描电镜观察颗粒物在细胞表面的附着状态,DHE荧光染色剂显色法测定细胞ROS生成情况,单细胞凝胶电泳实验检测细胞DNA损伤.结果表明,SiO2颗粒在超细粒径尺度(60 nm)下能抑制S.pombe细胞增殖,主要是通过附着在细胞表面来改变细胞外壁的通透性,并不能通过诱导细胞生成ROS而造成对细胞的氧化损伤;而平均粒径较大的PM2.5主要是通过诱导细胞生成ROS对细胞造成氧化损伤,同时可损伤DNA.结论认为PM2.5毒性大小与颗粒物粒径等物理性质并无直接关系.     

浮床栽培蕹菜根际脱氮微生物研究

浮床栽培植物是一种利用植物根系的吸收和根际微生物作用来改善水质的生物修复技术.本研究以温棚内浮床栽培蕹菜试验为基础,采用PFU法定期监测脱氮细菌变化情况,并与水中总氮含量进行对比,分析在浮床栽培植物情况下脱氮细菌的特征及其与水中总氮含量变化的关系,结果表明:1)栽培蕹菜有利于脱氮细菌的稳定生长;2)脱氮细菌的生长与总氮的去除有良好的相关性.研究为浮床栽培植物净化水质提供了理论依据,对该技术的推广应用有一定的理论和现实意义.表5,参10.     

Syntrophic co-culture of Bacillus subtilis and Klebsiella pneumonia for degradation of kraft lignin discharged from rayon grade pulp industry

In order to search the degradability of kraft lignin, the potential bacterial strains Bacillus subtilis (GU193980) and Klebsiella pneumoniae (GU193981) were isolated, screened and applied in axenic and co-culture conditions. Results revealed that mixed culture showed better decolorization efficiency (80%) and reduction of pollution parameters (COD 73% and BOD 62%) than axenic culture. This indicated syntrophic growth of these two bacteria rather than any antagonistic effect. The HPLC analysis of degraded samples of kraft lignin has shown the reduction in peak area compared to control, suggesting that decrease in color intensity might be largely attributed to the degradation of lignin by isolated bacteria. Further, the GC–MS analysis showed that most of the compounds detected in control were diminished after bacterial treatment. Further, the seed germination test using Phaseolus aureus has supported the detoxification of bacterial decolorized kraft lignin for environmental safety. All these observations have revealed that the developed bacterial co-culture was capable for the effective degradation and decolorization of lignin containing rayon grade pulp mill wastewater for environmental safety.     

垃圾渗滤液一体化生化处理工艺研究

垃圾渗滤液水质十分复杂,不仅含有耗氧有机污染物,还含有各类金属离子和植物营养素(氨氮等),工业垃圾渗滤液中还会含有有毒有害的污染物;其中有难以生物降解的萘、菲等非氯化芳香组化合物、氯化芳香组化合物、磷酸酯、邻苯二甲酸酯、酚类化合物和苯胺类化合物等;垃圾渗滤液中含有十多种金属离子,其中的重金属离子会对微生物产生抑制作用;氨氮含量高,C/N比例失调,磷元素缺乏,给生物处理带来一定的难度.本文开发了UASB-GAIA-BAF一体化生化处理工艺,以节约成本,提高垃圾渗滤液中有机物去除率,加快反应速率为目的,对厌氧生物处理、高级氧化处理、固定化生物滤池组合工艺降解垃圾渗滤液进行了初步设计和工程应用.处理工艺具有工艺成熟、投资省、运行费用低、污泥产生量小的优点.